![Half-helmet with an ANSI certified [25 dB NPR/CSA Class A/SLC (80) 24.7 Class 4] active noise control (electronic noise cancelling) earmuff. RESULTS AND DISCUSSION Half-Helmet without Hearing Protection In the absence of hearing protection the noise associated with cycling was substantial. At idle a sound level of 77 dB was observed in the 1/3 rd octave band centered at 100 Hz. The noise associated with motorcycling increased with velocity, and became prominent for velocities above 40 km/h. At a velocity of 120 km/h (about 75 mph) noise levels of 108 dB were obtained in 1/3 rd octave bands centered at 100 Hz, 125 Hz, and 200 Hz (Fig. 3). Furthermore, at 120 km/h the observed noise levels exceeded 100 dB for all ten 1/3 rd octave bands sampled from 50 Hz to 400 Hz. TrueRTA calculated a value of 118.1 dB for the total spectrum of the noise sample using a linear dB (flat) scale. Fig. (3) also shows that the noise level peaks occurred in the](https://www.researchgate.net/profile/Charles-Brown-20/publication/228481761/figure/fig2/AS:340732788396053@1458248435786/Fig-2-Half-helmet-with-an-ANSI-certified-25-dB-NPR-CSA-Class-A-SLC-80-247-Class_Q320.jpg)
![Helmet noise as a function of velocity for five studies{purple and blue X for full-face and open face helmets respectively [6], green triangles [25], red squares [26], blue diamond [34], the present data is shown with tan circles}.](https://www.researchgate.net/profile/Charles-Brown-20/publication/228481761/figure/fig4/AS:340732788396058@1458248435884/Fig-5-Helmet-noise-as-a-function-of-velocity-for-five-studiespurple-and-blue-X-for_Q320.jpg)
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Motorcycle Helmet Noise and Active Noise Reduction
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The incidence of collisions between motorcyclists and other vehicles may be significantly reduced by research that improves the acoustic awareness of cyclists, and thus heightens the ability of cyclists to respond to unexpected incursions from the surrounding traffic. We use our hearing as an early warning system, and hearing swiftly redirects our vision and attention. This shift in gaze is critical to our capacity to assess the location, direction of travel, and velocity of approaching vehicles. The present study was composed of two experiments. In the first experiment a Neumann KU-100 dummy head with embedded binaural microphones was used to measure noise levels in a motorcycle helmet as a function of velocity. Noise levels were measured in two helmets, one with active noise reduction technology, and one without. The results showed that noise levels exceeded 100 dB (A) at highway speeds in the absence of noise reduction technology. The helmet with active noise control ear muffs was able to attenuate helmet noise by up to 26 dB. Active noise control technology shows great promise for noise reduction for the motorcycle helmet industry, and the development of "quiet" helmets is important for both hearing conservation and highway safety. The second experiment surveyed subjective perceptions of helmet noise by motorcyclists. The results from the present sample showed that 92.1% of the respondents objected to the high noise levels associated with cycling, 63.5 % wore earplugs, 46.8% reported tinnitus, and 95.2% wanted a quieter helmet.
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... This noise increases with speed and is generated by the interaction between the helmet and the surrounding air, mainly associated with turbulence effects [6,7]. Other noise sources, like the motorcycle's engine noise or the effect of the motorcycle tires on the asphalt are not significant above 65 km/h, and therefore are not considered here [8,9]. ...
... The use of a neck seal has proven to reduce up to 4 dB at 120 km/h, but it can be difficult to fit in many situations and the wind can pull it out of the helmet [8,14]. In addition, the reduction of air flow within a helmet can lead to a buildup of CO 2 and heat, which could cause impaired cognitive performance [6]. ...
... In 1997 [13] the use of noise-canceling earphones in full coverage style helmets was patented, and it proved that the use of ANC techniques does not present the disadvantages of passive ones. Nevertheless, there are very few ANC works on motorcycle helmets [6,7,13,17], probably due to the timevarying nature of the noise dynamics. ...
In this work, three experiments are conducted. In a realistic environment (freeway), a database for the noise dynamics versus velocity in a motorcycle helmet is computed. Next, under the controlled conditions of an anechoic chamber, the models for the feedback (FB) and feedforward (FF) paths in the helmet are obtained by a filtering and identification process. Finally, in the same chamber, a hybrid (FB+FF) robust controller is tested against the actual noise measured in the freeway, and it achieves attenuations between 20 and 30 dB.
... However, these audio/visual interfaces are not suitable for motorcyclists, since they require their visual and auditory channels to maintain awareness of the environment around them. Such interfaces could obstruct the motorcyclist's view, decrease their acoustic awareness, and magnify their inatten tion while traveling, which in turn raises the probability of be ing involved in an accident [7,9]. Audio interfaces have also been proven in military field tests to throw off team comman ders' sense of direction from other audio inputs; commanders donning wearable audio devices (e.g., earbuds) only realize gunfire being directed at them after observing other team members with unimpeded listening ducking for cover. ...
... For motorcyclists, the use of the auditory channel comes with certain limitations and increased risk as it reduces acoustic awareness. Motorcyclists need to have acoustic awareness in order to respond to unexpected events [9]. Moreover, external noises such as engine or wind turbulence noise could make directional signals inaudible. ...
... Moreover, external noises such as engine or wind turbulence noise could make directional signals inaudible. At 70 mph, the wind turbulence is approximately 100 dB and is a major source of noise at high speeds [9]. The Psychological Refractory Period (PRP) states that when two tasks require simultaneous response, users decide on performing one task and queue the response for the secondary task. ...
A national study by the Australian Transport Safety Bureau revealed that motorcyclist deaths were nearly thirty times more prevalent than that of drivers of other vehicles. These fatalities represent approximately 5% of all highway deaths each year, yet motorcycles account for only 2% of all registered vehicles in the USA. Motorcyclists are highly exposed on the road, so maintaining situational awareness at all times is crucial. Route guidance systems enable users to efficiently navigate between locations using dynamic visual maps and audio directions, and have been well tested with motorists, but remain unsafe for use by motorcyclists. Audio/visual routing systems decrease motorcyclists' situational awareness and vehicle control, and thus elevate chances of an accident. To enable motorcyclists to take advantage of route guidance while maintaining situational awareness, we created HaptiMoto, a wearable haptic route guidance system. HaptiMoto uses tactile signals to encode the distance and direction of approaching turns, thus avoiding interference with audio/visual awareness. Our evaluations demonstrate that HaptiMoto is both intuitive and a safer alternative for motorcyclists compared to existing solutions.
... Wind creates a unique noise exposure to the motorcyclists influenced by the transmission through the helmet (J Kennedy et al., 2014). Continuous exposure to noise levels above 80 dBA over an extended period can affect the quality of life among young motorcyclists such risk for hearing damage (J Kennedy et al., 2014), Brown & Gordon, 2011 reported that high to moderate noise levels hindered reaction times, impaired attention and reduced perceptual and behavioural response effectiveness. In recent studies on young motorcyclist's (19-25 years), increased physiological stress reaction (Anila ; (Anila ; (Anila , cognitive decline (Anila Ali & Hussain, 2018b);(Anila Ali & Hussain, 2018a), diminished quality of life (Anila and poor audiometry profile (Anila were reported. ...
... External factors were summarized by Carley et al., 2011a as wind speed and direction, engine capacity, windscreen alignment, helmet type, and riding position or posture. Several different types of instruments were used in motorcycle noise assessment in these studies which included: Sound Level Meter (SLM) (Carley et al., 2010); ; (Violini et al., 2015); (García Violini et al., 2016), Digital Recording Tape (DAT) and tape analyzer (Harvey et al., 2002); (Ross, 1989b); (Chris Jordan, Oliver Hetherington, Alan Woodside, 2004); (John (Van Moorhem WK, Shepherd KP, Magleby TD, 1981); (Brown & Gordon, 2011), multiple memory noise logging dosimeters (Binnington et al., 1993), and 16 Channel Data Acquisition (DAQ) system (Carley et al., 2011b); (J Kennedy et al., 2014); (John (J Kennedy et al., 2013). All studies emphasized the effects of motorcycling on occupational motorcyclists. ...
Motorcyclists (n=26) average noise exposure levels (LAeq) were found substantially different for OSHA-HC (85 dBA), OSHA-PEL (78 dBA) and ACGIH/NIOSH (87 dBA) noise standards. A significant difference in LAeq, (p=.027) and engine capacity usage (p=.045) was found amongst gender. However, no observable association was found between the LAeq and motorcycle engine capacity (p= .462) and completion of a ride (p= .695). Thus, female riders were inclined to use lower motorcycle capacities, rode at lower speeds which resulted in lower noise exposure levels, in concurrence with longer ride durations. Overall, motorcyclists’ noise exposure level functions with the increasing speed (80km/h: 88 dBA). Keywords: Motorcycle noise; Dosimeter; Speed; Noise standards eISSN: 2398-4287© 2020. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open access article under the CC BYNC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia. DOI: https://doi.org/10.21834/ebpj.v5i15.2455.
... High noise exposures can affect the hearing of such exposed population that can suffer in hearing sensitivity with the reduction of 30db or more and possible distraction (Carley et al., 2010). The hearing ability acts as an early warning system and swiftly redirects our vision and this gazing shift is critical to assess the location, direction of travel and speed of approaching vehicles (Brown and Gordon, 2011). ...
... In the literature little work is available on the nature and sources of noise exposed to riders and its effects other than hearing disabilities, particularly to occupational motorcyclists . It was shown that high to moderate noise levels hindered reaction times, impaired attention and reduced perceptual and behavioral response effectiveness (Brown and Gordon, 2011). It was reported that virtual stimulus paired with an auditory cue results in more accurate visual perception, increased the risk of accidents and increased level of stress (young riders) (Perroti et al., 1990;Ali et al., 2016;Ali et al., 2017). ...
At-ear noise exposure assessments of motorcyclists, with the function of speed, would be unsafe as on-road data acquisition has certain constraints including the operations and portability of appropriate instrument. Currently, there are no standardized protocols and methods for measuring the noise under motorcycle helmets. Furthermore, standard permissible noise emission levels for commuter motorcyclists are also not defined. Therefore, this study was aimed to investigate the motorcycle noise exposure assessments in realistic environment among young riders. A personal dosimeter was utilized to calculate the daily noise exposure level (L Aeq , 8h) under three different standards including: OSHA-HC Personal dosimeter results (n=52) revealed the average noise exposure level of 93.64 dBA, 92.51 dBA, 95.29 dBA for OSHA-HC, OSHA-PEL and ACGIH/NIOSH respectively. The mean Time-Weighted Average (TWA) was 76.82 dBA, 75.69 dBA, 85.16 dBA for OSHA-HC, OSHA-PEL and ACGIH/NIOSH respectively. Under the ACGIH and NIOSH standard, the TWA for motorcyclists is at hazardous limits, which requires further investigations associated with health effects on riders. Standardized methods and configurations should be set for assessing noise exposure related to the motorcycling.
... There is no doubt that, when fitted properly and worn consistently, HPDs offer significant noise attenuation, and perhaps this is why HPD usage is now increasingly being observed in a variety of noisy non-work (or leisure) settings. Earplugs are regularly worn by people riding motorcycles [13] and playing music [14,15], while those using home power tools commonly opt for ear muffs. The few researchers who have investigated HPD usage in leisure settings have found that it is more widespread in activities such as shooting and motorsports than in musicrelated activities [16,17], such as nightclubs and music concerts. ...
... However, other studies find no link between gender and HPD use [16], and yet others suggest females are more likely than males to use HPDs, at least at pop concerts [18]. 13 Age played a significant role in HPD use in nightclubs, concerts and fitness classes, suggesting that those who continue with these activities beyond their youth become "older and wiser" and choose to protect their hearing while their younger counterparts remain either oblivious to the hearing risk or unwilling to mitigate it. This concurs with a Swedish study showing older Swedish adolescents were more likely than younger adolescents to wear HPDs at discotheques and concerts [16]. ...
Use of hearing protection devices (HPDs) at work is widespread and well researched, but less is known about HPD usage in high-noise leisure activities. This study investigated 8,144 Australians' HPD usage in leisure settings. An online survey asked questions about HPD usage at work and leisure, and examined whether age, gender, HPD usage at work, and tinnitus predicted HPD usage in leisure activities. Leisure-based HPD usage was most common during high-risk ‘work-related’ activities. Use of HPDs at work was the most significant predictor of leisure-based use, with workplace users up to 5 times more likely to use HPDs at leisure. Males were significantly more likely than females to use HPDs in 10–20 leisure activities, and those with tinnitus were more likely than those without to use HPDs in 8–20 activities. Older participants were more likely to use HPDs at nightclubs and concerts, but younger participants were more likely to use HPDs playing egames and musical instruments.
... For as little as $5-10 USD per pair, "musician's earplugs" provide much more uniform attenuation across frequency, allowing for nearly distortion-free listening, and for some people, even improved speech understanding in loud background noise [216][217][218]. Another option is an active noise-canceling headphone [219][220][221]. Stage musicians can protect their ears while improving their ability to hear their music by wearing "in-ear monitors", which are Bluetoothed to the amplification system [222]. ...
High sound levels capable of permanently damaging the ear are experienced not only in factories and war zones but in concert halls, nightclubs, sports stadiums, and many other leisure environments. This review summarizes evidence that loud music and other forms of “leisure noise” are common causes of noise-induced hearing loss, tinnitus, and hyperacusis, even if audiometric thresholds initially remain within clinically normal limits. Given the huge global burden of preventable noise-induced hearing loss, noise limits should be adopted in a much broader range of settings, and education to promote hearing conservation should be a higher public health priority.
... The acoustic environment is important both for the riding experience and for rider safety. Surveys of riders [24] have reported rider hearing damage in the form of tinnitus, and the majority of riders express the desire for quieter helmets, with over half of them wearing earplugs when they ride as a noise reduction method. Ear-plugs do not, however, distinguish between sounds and so block out sounds that the rider may need to pay attention to such as some traffic noise and emergency sounds. ...
Noise transmission characteristics of a motorcycle helmet have been analysed using a combination of insertion loss measurements and loudness matching in a behavioural study. Results demonstrate the action of the motorcycle helmet as a spectral filter. The insertion loss measurements confirm previously published data showing attenuation in the frequency range above 500Hz. A further feature, the significance of which is addressed and highlighted here for the first time, is an amplification of noise below 500Hz. In short, the helmet acts as a frequency dependent filter on the input to the human auditory system. Data from the matching task were used to generate equiloudness curves which show the effect of the helmet on riders' perceptions of loudness. The generated curves were compared to the international standards (ISO226). The character of the equal loudness curves was strongly influenced by the helmet. This difference is discussed in the framework of the filtering characteristics of the helmet.
... There have been a variety of medical studies that confirm that the prolonged exposure to excessively noisy environments may cause health problems, such as, noise-induced hearing loss (NIHL) [1][2][3][4]. Active noise control (ANC) has an extensive reference bibliography [5,6], but there have been very few ANC works on motorcycle helmets [1,[7][8][9], probably due to the time-varying nature of their dynamics. ...
The active noise control problem in motorcycle helmets is studied, which has an intrinsic time-varying behavior. The time-varying approach is designed to have an attenuation level that increases with the speed between the helmet and the air using a linear parameter-varying (LPV) controller. To achieve a reasonable noise attenuation, the noise source and its dynamic characteristics are computed. Three different experiments were performed, an experiment on the noise dynamics, identification tests and an experiment on controller implementation. The identification tests were carried out using six sinusoidal sweeps as system excitation signals. Between each sweep, the system was perturbed to include various practical situations. Regardless of the attenuation results, the alternative of having a controller that changes its performance as a function of the helmet speed is attractive.
... Surveys of riders [24] have reported rider hearing damage in the form of tinnitus, and the majority of riders express the desire for quieter helmets, with over half of them wearing earplugs when they ride as a noise reduction method. Ear plugs do not, however, distinguish between sounds and thus block sounds to which a rider may need to pay attention, such as some traffic noise and emergency signals. ...
Noise is an unavoidable component of motorcycling. The noise sources are varied, and include the helmet itself which also filters the noise passing through it. Here helmet noise transmission characteristics have been analyzed using insertion loss measurements and loudness matching in
a behavioural study. Results demonstrate the action of the helmet as a spectral filter and confirm previously published data showing attenuation in the frequency range above 500 Hz. Highlighted here for the first time is an amplification of noise below 500 Hz. The loudness matching task data
allowed the generation of equiloudness functions which show the effect of the helmet on riders' perceptions of loudness. The generated curves are here compared to the relevant international standard (ISO226) and show that loudness was strongly influenced by the helmet. The noise experienced
by a motorcycle rider on a 30 minute journey can result in a temporary hearing threshold shift of over 15 dB. Due to the filtering characteristics of the helmet this threshold shift is highly frequency dependent. To quantify the frequency dependence of the resulting temporary hearing threshold
shift pure tone audiometry was conducted before and after exposure to white noise, with and without a helmet in a laboratory setting and after on-road noise exposure. Of particular note is the finding of increased hearing sensitivity at high frequencies following certain type of motorcycle
noise exposure. The difference is discussed in the framework of the filtering characteristics of the helmet.
The maritime sector is exploring the applicability of alternative powering options and ways to implement new technologies to increase safety, efficiency, and autonomy of ship power systems. The technological development of power systems, their complexity, and high costs of their malfunction or downtime have led to employment of different approaches in safety engineering. In order to reduce hazards and failures in ship operation, shipbuilders use several methods during design phase to identify, investigate and manage all safety concerns. For this purpose, there is range of methods, as for instance Fault Tree Analysis (FTA), Event Tree Analysis (ETA), Failure Mode Effects Analysis (FMEA), and Failure Mode, Effects and Criticality Analysis (FMECA), which can be used separately or combined. This paper reviews these methods with their advantages and limitations in their application to risk assessment of ship power systems.
Hearing is a function of the acoustic signal and the properties of the environment that structure the sound. To better understand how hearing is affected by structural properties, the current research investigated the impact of football helmets for hearing. Speech signals were broadcast at three angles of incidence (0°, 45°, or 90°) to an artificial dummyhead recording device wearing a football helmet (experimental condition) or without the helmet (control condition) to make binaural recordings using condenser microphones positioned at the location of the tympanic membrane. Acoustic analyses revealed that the helmet caused frequency-specific changes to an auditory signal, including both positive and negative interference that varied in relationship to the angle of incidence. Behavioral studies showed that while; in general, the football helmet made hearing speech more difficult, the magnitude of the decrement was a function of the amount of spectral change induced in the speech signal. Results are discussed in terms of the implications of an ecological approach to hearing and the design of helmets.
Measurements of the at‐ear noise attenuation provided by several popular motorcycle helmets were made. To do this, a probe microphone was placed in a subject's ear. He then operated a motorcycle through a test cycle, which included the motorcycle's entire performance range. He then donned a motorcycle crash helmet and repeated the test cycle. In each case the at‐ear noise was recorded and analyzed. A comparison of the analyses revealed the attenuation characteristics of each helmet tested. In addition to helmet manufacturer, helmet size and type of eye protection fitted were varied. Three different subjects were used to establish differences from person to person.
On the basis of earlier work and informal observation it was suspected that the effect of loudness on simple rt could not be accounted for by changes in the time it takes the s to hear the stimulus. 2 experiments, each using 8 naval rating volunteers, are described in which an increment in the level of background random noise is presented to the S. The effect of increment size on rt and on a simultaneity judgment are investigated using a range of increments from just above difference threshold to moderately loud and clear. The difference in the size of loudness effects in the 2 tasks lends some support to a model which explains the influence of loudness on rt largely in terms of latency of response initiation. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Motorcyclists are known to be exposed to excessive wind noise levels when riding. The potential adverse effects of this exposure on their hearing was investigated. Temporary threshold shift (TTS) was assessed by asking 18 riders to undertake a standard test run of one hour at a steady 80 mph, and performing audiometry before and immediately afterwards. Permanent threshold shift (PTS) was assessed by performing pure-tone audiograms on a highly screened group of 246 motorcyclists and comparing their hearing thresholds with those of an appropriate control group obtained from the MRC National Study of Hearing.
Significant TTS was found at 0.25, 0.5,1 and 2 kHz. The greatest TTS occurred at 1 kHz, with a mean hearing loss of 10.3 dB. The hearing thresholds of the motorcyclists were significantly worse than the controls at 0.25, 0.5, 1 and 2 kHz, andwas most marked at 0.5 and 1 kHz where their hearing loss (PTS) was, respectively, 3.7 and 3.6 dB greater than expected.
These findings demonstrate evidence of both temporary and permanent hearing loss from motorcycling and present a strong argument for the need for some form of remedial action.
Recent noise at work regulations in the EU (2003) have been established to prevent noise induced hearing loss (NIHL). This imposes better performance results to traditional feedback active noise control (ANC) in motorcycle helmets, which suffer from well known limitations. Here two new ideas are applied to this problem. First, an hybrid (feedforward/feedback) linear time invariant (LTI) controller is designed for a motorcycle helmet ANC, which improves the resulting attenuation. This is achieved by adding an extra pair of microphones which measure the external noise that is then used as the feedforward input signal. In addition and to increase even more the resulting performance, the air velocity is measured in real-time and used as the parameter which schedules a linear parameter varying (LPV) feedback (FB) controller. This is combined with the previous feedforward (FF) controller, resulting in a time-varying hybrid controller. Both hybrid, LTI and LPV controllers are designed using linear matrix inequality (LMI)-based optimization. Two experiments have been carried out to measure the relation between external noise spectra and velocity: a wind tunnel test and a freeway ride experience. The resulting controllers are tested in a simulation which uses actual data obtained from the freeway experiment. The resulting attenuations in this motivating study seem promising for future controller tests to be performed in real-time, with the adequate hardware.